Why is ng-template in Angular 10 rendered twice?

Question

I figured out a problem with twice rendered components when a ng-template and ngTemplateOutlet are used. But why?

HTML:

<ng-template #options>
    <h3>I'm template</h3>
    <sidebar-options></sidebar-options>
</ng-template>

<div class="container-fluid">
    <div class="row">
        <aside class="order-2">
            <ng-container *ngTemplateOutlet="options"></ng-container>
        </aside>
        <div class="col order-1">CONTENT</div>
    </div>
</div>

Component:

import { Component, OnInit, Input, ViewChild, ComponentFactoryResolver, ChangeDetectorRef, ViewContainerRef } from '@angular/core';

@Component({
    selector: 'sidebar-options',
    templateUrl: './sidebar-options.component.html',
})
export class SidebarOptionsComponent implements OnInit {
    @ViewChild('container', { read: ViewContainerRef, static: true }) container: ViewContainerRef;
    @Input('types') types: OptionType[];

    constructor(private cfr: ComponentFactoryResolver) {}

    ngOnInit(): void {
        console.log('ini');
    }
}

How can I prevent that the SidebarOptionsComponentis rendered twice?